i use something similar to what lizzi said - when people try to tell me i cannot possibly be eating enough, the plan I am on cannot be good for me or is really weird (it is fruits/vegetables/protein) I have learned to smile and say "I am being consistently monitored by a physician and if he tells me my body is not healthy he will also help me figure out what I need to differently". the most ironic thing is the most vocal person in all this has since done the same plan - so smile and come up with a stock "I will know if I need more..." type answer and say it over and over!

Thank you for the advice.

Tell him you appreciate his offer. You are trying to eat healthy.

Tell very polite. You know. What you like.